Raise the boost, push it hard, you get more heat and it's harder to get a spark. Result is the stock plugs start to misfire.
 

Answer, colder plugs. But not only that, plugs that are of a different design. There is an article on plugs at Yawpower, that discusses the advantages of a more exposed electrode. I suspect that the combination of a smaller gap and exposed electrodes has eliminated the misfires I have been experiencing.